Electrical signaling system



June 16, 1942.. R. TAYLOR ET Al. 2,286,445

ELECTRICAL S IGNALING SYSTEM Filed March 1, 1940 5 sheets-shet 1 c E7/g f B E A 90o ,wooo' TL- wn v 78900 2W* 0000 v A I 2 U/s mmm l @607:99 (figa/laf@ Attorney June 16, 1942. R. TAYLOR ETAL ELECTRICAL SIGNALING SYSTEM 5 Sheets-Sheet 2 Filed March l, 1940 Tol( I l l l l l l l I I l I l I l l l Toll( l l l l l l l l l l l l l l l l l l l l l l l I Te l l l 1 l l 1 u x Tol( l l l l I l l l I l l l l l l l .|.I.

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ELECTRICAL SIGNALING SYSTEM Filed March l, 1940 5 Sheets-Shea?l 4 June 1,6, 1942. R. TAYLOR ET AL 2,286,445

ELECTRICAL SIGNALING sYsTEM y Filed March l., 1940 5 Sheets-Sheet 5 I/g. 3'." s

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Patented June 16, 1942 Utili@ STS Piaviiei'i WWE@ @if il' ELECTRICAL SIGNALING SYSTEM lil.

Application March 1, 194i), Serial No. 321,783 in Great Britain March 2, 1939 16 Claims.

The present invention concerns improvements in or relating to electrical signaling systems particularly for identification purposes and while it has particular application to identifying lines in a telephone connection it, of course, has application to other kinds of systems where lines are adapted to be connected together in different combinations.

One of the applications of the invention in particular is for ascertaining the number of a calling line and also for registering the same. On the other hand, the invention can also apply not only to ascertaining and registering the number of a calling line or point but also for ascertaining and registering the identity of any line in a connection at another point in the connection remote from said line.

In the case Where a switch is tied to a line the identification will of course apply to the switch as well as to or alternatively to the line,

In telephone systems a connection is effected by a series `of selecting operations starting from the calling line and terminating at the called line in which there area number of lines or switches, relays or their equivalent taken into use under th@` numerical or directional control of the calling party or independently thereof, and it is frequently desirable to know at one point of a connection particulars of another point of the connection which is connected up. For instance, this could be made use of in tracing a connectioneither backwards or forwards, and in particular it is of value in determining and ascertaining at a common point the number of a calling line.

Previous methods for obtaining this result have usually involved firstly a search for the calling line and secondly the transmission of the identity of the calling line once it has been found. Such arrangements render it possible to only identify one call at a time and the same apparatusI cannot be used for identifying other lines until the identification of a previous line has been completed. The object of the present invention is to enable a number of lines to be identified in the same period of time. In this way the same identification equipment may be utilised to identify more than one call at a time.

According to one feature of the present invention in a telephone or like systemin which conmi nections are adapted to be extended to, through or from certain points, a distinguishing signal is made available to each of said points irrespective of whether connections requiring identication extend to, through or from said points or f not so that all the points to, through or from which such connections extend may be identified The expression extended to, through or from certain points is intended to imply that the point to be identified may be a called line or fil? its equivalent, it may be some intermediate point of a connection or it may be a calling line.

According to a further feature of the invention two progressively operated switching means are provided, one adapted to effect successive momentary connections with the line or apparatus to be identified, while the other, which is associated with a part of the connection where identication is to be made or registered and opcrates in step with the first switching means, is adapted to effect successive momentary connection with apparatus by which the identification is made or registered. The progressively operated switching means preferably operate in a continuous manner at least from thetime that their operation is initiated until they have made one complete cycle of movement so that a number of lines in suitable condition can be identified during one cycle, but it must be understood that while the movement of the progressively operated means can be of a regular character it could also be of an irregular character provided that the movement `of the two progressively operated means correspond, It is not essential that the progressively operated means should operate for every call but they can be controlled to operate only if certain connections are being set up.

According to a further feature of the invention one of two switching means operating in step is adapted to apply an impulse or impulses at a point in a connection which requires identifying at another point in a connection, while the other associated with said other point of the connection connects up different pieces of apparatus so that the piece of apparatus connected up at the instant an impulse is transmitted by the first switching means, is operated. Preferably such switching means are located in the same exchange so as to have common driving or controlling means and may comprise different wipers of a switch, certain wipers for establishing a circuit over a connection and the other Wipers for determining the selecting operation. Conveniently, in order to enable a larger number of identifying signals to he transmitted the number of circuits established over a connection may be increased provided the connections are completed at distinct instants of time. Alternatively, signals represented by distinctive operating currents may be transmitted over the same connection and possibly over the same line at the same instants of time to give different identifications.

According to a further feature of the invention where the identity of a, certain point in the system is represented by a number of digits or equivalent component identifying features the transmission of the identity of such a point to some other point is effected by a switch having movementl in a single direction to an extent measured by a number of contacts equal to the product of the numbers of impulses in a cycle required to transmit each digit, certain combinations of contacts being used for each digit, and a plurality of bank contacts being provided to cater for the total number of combinations it is desired to use.

According to a further feature of the invention each distinctive identifying feature of the identity to a point or line in a connection is adapted to be transmitted by a distinctive combination of a plurality of pulses of a cycle.

According to a further feature of the invention corresponding cyclic operations at the transmitting and receiving ends which may be initiated either1 from the connection itself or over another connection or even independently of any connection cause an impulse or impulses to be sent and received over a connection at an instant or instants in the cycle which is or are jointly distinctive of the identity of the calling line without necessitating the sending of a starting impulse or signal to indicate the beginning of a cycle.

According to a further feature of the invention the transmission of the number of a line over a connection is adapted to be effected by a plurality of distinctive impulses repeated in cycles so that irrespective of the order in which the distinctive impulses are transmitted the receiving apparatus is operated in the same way.

Certain of the forms which identification equipment may take for carrying out the features of the invention mentioned above are best adapted for dealing with one or two digits only and in fact such forms are particularly advantageous for use in exchanges of small capacity. According therefore to a further feature of the invention part of the identificatiion of a line takes place at one point of the connection and the remaining part of the identification of the line takes place at another part of the connection. For instance, part of the identification of a calling line takes place at the calling line itself while the other part of the identification takes place at a point common to a number of calling lines, for instance at an outgoing relay set associated with a junction line leading from an exchange.

According to a further feature of the invention part of the identication of a line takes place when a certain control is exerted after a connection from a, line has been set up in a certain traffic direction and is stored at a point to which a number of lines have access which have corresponding parts of their identification different while the remaining parts of their identification are the same, the complete identification being subsequently transmitted from said point to the position at which it is required.

Preferably the identification of a line in an exchange in a network is initiated only in connection with certain calls and stored and subsequently the complete identication of the line including the identification of the originating exchange is transmitted to the position at which it is required. For instance, the initiation may take place when a line outgoing in a direction in which identication may be required is taken into use or when the called subscriber responds. Alternatively the initiation may take place at the termination of a call or in response to a signal initiated by an operator to whom the call may be routed. In these latter cases it may not be necessary to store the identification of a line in an exchange as it could be arranged to transmit it direct after the exchange identity has been transmitted. The invention is particularly suitable for dealing with networks comprising main exchanges, satellite exchanges associated with one or more main exchanges and a central exchange which may also be a main exchange to which the numbers of calling lines are transmitted for toll ticketing, toll recording or display and in which identification equipment is associated with the outgoing trunk lines of each satellite and main exchange by which the identity of the calling line as distinguished from that of the calling exchange is first stored and by which the identification of the called line as well as a calling exchange is subsequently transmitted to the central exchange.

The invention enables provision for what is generally known as automatic toll ticketing to be made in automatic telephone systems with very little modification thereof, being capable of application both to exchanges of the individual line switch or common line finder type. In exchanges where toll operators are employed the invention could moreover be utilised with advantage for calling number verification purposes and it might also be arranged that when a subscriber sets up a connection to a toll board the identification equipment is automatically brought into operation to display the calling number in front of the toll operator thus rendering unnecessary the demanding and verification of the calling number. The scheme may be utilised at phonogram positions for identifying calling lines and also testing positions for ascertaining the numbers of faulty lines, particularly those on which the calling condition is simulated.

Other 4applications of the scheme both to telephone and like signaling and/or control systems will be apparent to those versed in the art.

These and other features of the invention will be better understood from the following description of one method of carrying it into effect, reference being had to Figs. 1 to 9, which illustrate one example of carrying the invention into effect as applied to automatic ticketing, although it will be understood that the invention is capable of much wider application as is indicated herein.

Fig. 1 shows part of a typical 5 digit exchange network layout in which are included four exchanges A-D together with a central exchange E via which all toll calls to distant exchange networks are assumed to be made.

All exchanges are furthermore assumed to be of the individual rotary switch type in which each subscriber is provided with an individual uniselector, this type of exchange having been chosen for the purposes of illustration as it is believed to representl one of the most difficult systems in which to locate 'a calling number.

Fig. 2 shows the trunking principles involved in the setting up of a toll call from the satellite exchange A.

Fig. 3 shows the invention applied to identification of calling lines in groups of or in an exchange of up to one hundred lines capacity. the signaling being on a time basis and utilising more than one signal of the same kind for each subscriber, the signals characteristic of the various subscribers numbers being transmitted at different instants and with a diierent time spacing therebetween so as to give the necessary discrimination. This principle is readily applicable to larger capacity exchanges. Fig. 4 shows typical wiring varrangements of the banks of the identic'ationsending and receiving switches.

Fig. 5 shows the essentials of the circuits of an outgoing relay set which are necessary for the purpose of illustrating how the calling line identication equipment can be started up and how re-transmission of the stored calling number can be effected when required.

Figs. 6 and 7 show a method of rapidly transmitting a calling number in code form from exchange A to exchange E together with a method whereby the required constant prex digits may be automatically added.

Fig. 8 shows in diagrammatic form an alternative method to that illustrated in Figure 3 of applying the invention to a small telephone exchange of up to about 25 lines capacity.

Fig. 9 shows a further alternative method of applying the invention to larger capacity exchanges, the signaling being again on a time basis as in the rst case but employing signals of different kinds. This method is capable of application to any size of telephone exchange.

Referring to Fig. 1 exchange E represents a main exchange linked with a number of other exchanges A, B, C and D having the same linked numbering scheme. The exchange E has toll lines TL linking it with other exchangel areas, calls to which are to be lautomatically ticketed or recorded for charging purposes. is necessary to have certain information and in particular the number of the calling line transmitted to the exchange E whether the calling line is connected to the same exchange or any other exchange including A in the area served by the linked numbering scheme. It will be asumed that the calling line to be identified is associated with exchange A. t is further assumed that this exchange is of 100 lines capacity with numbers extending from 78011-78000.

Referring to Fig. 2 it will be seen that a subscriber S, assumed to have the number '78011 and to have originated a call, will be routed over his uniselector U/S to a selector SR. a toll cali a suitable digit or digits will be dialled as a result of which a connection will be set up via the outgoing relay set ORS, local junction LJ, to exchange B equipment at exchange B, junction line J and incoming selector ISR on to a toll relay set such as TRS and associated toll line TL outgoing to a distant exchange network. Further digits dialled extend over the toll line to route the call to the desired destination.

In response to the setting up of such a connection calling subscriber identication equipment, to be described hereinafter and represented by switch SS in Fig. 2, is caused to rotate and cause la signal to be transmitted over the test conductor of the calling line indicative of part of the identicaticn of the calling line, in this instance, the last two digits 11, to the outgoing relay set ORS. Here, the preiix digits '780 characteristic of all numbers on the calling exchange A are added in a manner to be when the toll relay set TRS at the central exchange E requires the calling number for the purpose of toll ticketing, the full calling number 78611 is sent out from the relay set ORS and is either received at the relay set TRS or piloted v through this relay set to suitable ticket printing, recording or displaying equipment which will be associated therewith either on an individual or common basis.

It may be mentioned here that if the actual F To this end it A satellite exchanges such Ias Li.

If he requires a described and iii) display, recording or printing does not take place until after conclusion of conversation as is assumed to be the case, calling number identication may be carried out either immediately after a particular call has been set up and/or at any time during conversation Ias the identification may be effected over the test conductor. The identied digits of the calling number are then stored in the outgoing relay set ORS until conversation is concluded when transmission of the complete calling number to the central exchange may take place.

Before proceeding further it will be best to describe how the identification of the individual calling line is effected and before describing the more complex arrangement illustrated in Figure 3 it will be well to describe the arrangement illustrated in Figure 8 which represents a ten line exchange. In this case a subscriber such as Si having the calling number 7 or its last digit 7, on removing his receiver, will be connected over the intermediate distribution frame I. D. F. and his uniselector U/S to an idle selector SR. Assuming a toll call is required, a suitable digit will be dialled to route the call via the outgoing relay set ORS either to a toll operator or 0n to an outgoing toll line extending to a distant exchange.

For the purpose of identifying the calling number on such calls each relay set ORS is provided with a ten point uniselector RS, a signal receiving relay PUR and storage relays USRl-USRES for the respective calling numbers 1-0 of which only relay USR'i' is shown. The relay USR! is connected to the rst contact and the other relays to the other contacts in accordance with their numerical sufiix reference. A common ten point uniselector, to be known as the sending switch SS, is also provided and this switch is capable of impressing an identifying signal on any of the ten subscribers lines; for this purpose each contact on the bank of the switch SS is wired out individually to the private conductor P of each subscribers line circuit, the first contact to number I and so on.

When the outgoing relay set is operated to signify that identification of a calling line is required it simultaneously starts up both the switches RS and SS and these switchesl are arranged in any convenient manner, for instance their wipers may be arranged upon the same shaft to rotate in step with one another through a complete cycle. Switch SS in rotating momentarily applies an alternating current signal to the P conductor of each line circuit, but as in the presen instance subscriber Si only has completed a connection to a toll line the signals will not be made use of until switch SS reaches position 'l corresponding to the calling party. When it does so, a pulse of alternating current will be transmitted over the connection and will operate relay PUR. Contacts of this relay connect up with the wiper of the receiving switch RS which as it is rotating in step with wiper of switch SS will be on position 'i at the instant at which relay PUR is operated. The storing relay USR? will be therefore loperated to bring about the registration or indication of the digit 7 corresponding to the number or" the sub.- scriber calling.

With the above arrangement, and in fact all the arrangements embodying the invention, it will be appreciated that any number of separate calling lines can be identied during a cycle of operation of the identification equipment, all

line circuits from which a connection to a toll relay set has been set up being able to utilise the characteristic signal transmitted thereto and each allowing the signal concerned to be eX- tended to the relevant outgoing relay set where it will be registered or indicated in the manner described.

The arrangement described may be applied to larger exchanges by utilising selecting switches of larger capacity but since the number of storing relays at each toll relay set increases accordingly the scheme becomes correspondingly less economical with each increase in size.

To avoid this one alternative is described with reference to Fig. 9 as applied to an exchange assumed to be of 100 lines capacity in which all line numbers have only two digits or have the first digit or digits corresponding to the exchange designation the same and the last two digits representative of the number of the calling line in that exchange.

It will be seen that the arrangements follow on the same general lines as those of Fig. 8 with the exception that the receiving switch RS at each toll relay set is provided with two wipers RSI and RSZ which connect with two sets of storage relays USRl-HJ and TSR-l for the units and tens digits respectively of the calling numbers of which only URS? and TSRS are shown. The common sending switch SS is provided with two sets of wipers each represented by the single wiper SSI and SS2 respectively and corresponding banks, the wipers being connected to alternating current supply sources of two different frequencies fl and f2, frequency fl being utilised for the purpose of signaling the units digits and frequency f2 for the tens digits. For the purpose of signaling, the P conductor of each subscribers line circuit is connected to a Contact in each of the banks so that there must be ten wipers corresponding to SSI and ten wipers corresponding to SSZ in order to accommodate the 100 P conductors.

Typical connections are shown for No. 87 sub.- scriber (S87) who is assumed to have made a call to the relay set ORS and it will be seen that his P conductor is wired to contact l in one row of contacts engaged by wiper SSI and contact 8 in a row of contacts engaged by wiper SSZ. When the switches SS and RS are set into operation all the various wipers rotate in step with one another and hence frequency f l will be transmitted over the SSI wiper in position 'i to operate relay PUR over the connection set up, this relay being tuned either electrically or mechanically to the frequency fl. Relay PUR on energising operates the storage relay USR? corresponding to a units digit 7, While when the SS switch reaches position 8 frequency f2 will be transmitted and will operate the tuned relay 2PUR, which in turn brings about the operation of storing relay TSR8 corresponding to the tens digit 8.

It will be appreciated that this arrangement also enables a number of calls to be identified during one cycle of operation of the identifying equipment.

By utilising other signaling frequencies in conjunction with extra banks on the switches SS and RS this scheme can be extended to cover larger exchanges and it will be appreciated that it provides a very quick method of identification since in one rotation of the identification switches a calling number may be identified irrespective of whether it is large or small.

In the arrangement illustrated in Figs. 3 and 4- signals of the same kind but at different time spacings are used to determine the various calling numbers. In this case the receiving switch RS at each outgoing relay set is of the two Wiper rotating type with 25 contacts accessible to each wiper while the sending switch SS is of the 8 wiper rotating type with 25 contacts accessible to each wiper. These switches are capable of dealing with one hundred subscribers.

The P conductor of each line circuit is connected to two diierent contacts in the bank of the sending switch SS, the connections being spaced in such a manner so that both tens and units digits of a calling number can be signaled during one rotation of the switch.

Before proceeding in detail with the wiring of the switches SS and RS the general operation will be briefly reviewed. When it is desired to identify a calling line both the switches RS and SS are caused to rotate in step with one another through a complete cycle back to their home position. Switch SS in rotating applies two signals to the P wire of each of the subscribers, each pair of signals being indicative of two digits of a subscribers number and comprising two pulses of alternating currentl applied at particular instants and with a suitable spacing therebetween so as to give the necessary discrimination between diTerent numbers. Although signals are transmitted to conductors connected or adapted to be connected to the P wires of all line circuits, only those line circuits from which a connection to an outgoing relay set such as ORS leading towards a toll line such as TL (Fig. 1) has been set up will make use of the signals and in the present instance the signals indicative of the number of the calling subscriber S will be extended to the relay set ORS and operate the signal pick-up relay PUR accordingly. Contacts of this relay connect up with the receiving switch RS which rotates in step with switch SS and will bring about the translation of the signal by virtue of storing relays which are operated in particular combinations over the wiper and bank of the switch RS.

Referring to Fig. 4, this shows the bank layout of the common sending switch SS and of a receiving switch RS provided in association with each toll relay set ORS. It will be seen that the eight wiper SS switch bank is divided up into iive groups marked V-Z, each having ve rows of eight contacts in a row, each row of contacts being also distinctively labelled with one of the letters V-Z. The wipers in rotating, successively engage with each row of contacts and connect an alternating current supply thereto via the direct current isolating condensers C|-C8.

Considering now the exchange numbering scheme, two digits only are to be identified, the numbers being grouped for convenience in the usual way for automatic telephony:

For the purpose of signaling a calling number to the toll relay set a two letter code is employed for each of the numerals 1-0 irrespective of the digit to which it applies, as follows:

It is assumed that subscriber 78011 has initiated a toll call and it is desired to identify the last two digits 11. In this instance it will be necessary to signal VW. VW. to the toll relay set. On referring to the bank SS it will be seen that the P wire of subscriber No. 1i is connected to one of the contacts on both of the rows i and 1. The wipers in rotating over these positions will therefore extend an A. C. pulse over the connection shown in Fig. 1 and will operate relay PUR accordingly. The receiving switch RS at the toll relay set will be in step with switch SS and hence relay PUR in operating will extend a potential on to the wipers when they are in positions l and l. As a result, the storing relays V and W connected to the right-hand set of contacts will be operated registering the units digit l while the storing relays V and W connected to the left-hand set of contacts will be operated, in addition registering a tens digit 1 These two digits l1 of the calling subscribers number, after one rotation of the switch SS, are thus stored in the outgoing relay set ORS.

It will be noted that if the P wire of the subscriber the last two digits of whose number are 11, was connected to contacts in rows 2 and VW. VW. would still be signalled, so that actually all numbers of two digits have two alternative connections to give the same signal and theactual wiring connections employed will be such as to enable all contacts to be utilised so that the capacity of the switch need only be a minimum, in this case 200 contacts in all.

Assuming that the last two digits of the calling line number are 21, it will be necessary to signal VX. VW. and hence the P wire of the subscriber may be connected to one of the contacts on rows 2 and H. Signals are therefore sent out in these two positions and bring about the operation of the tens storing relays V and X together with the units storing relays V and W.

Although the connections to the bank SS are shown as made to the outer contacts of each row only,y it will be understood that this is merely for convenience of drawing and that any of the contacts in a row may be utilised without affecting the code transmitted. Typical connections in regard to certain subscribers lines are shown and the connections for the remainder of the subscribers lines may be readily visualised if consideration is first given to the code required for each particular digit in the number concerned.

This scheme, while applicable to small telebe connected to two contacts in the bank of a thousands and hundreds switch. Two RS switches may also be provided in each toll relay Vset instead of one. In this case .either different frequencies will be used for the tens and units digits and the thousands and hundreds digits as described with reference to Fig. 9 or the SS switch and RS switch corresponding to the thou.. sands and hundreds digit will be operated alter-.- nately with the SS switch and RS switch corresponding to the tens and units digits.

Assuming a subscribers number is 36111 (i. e. a subscriber connected to exchange C) the P conductor will be connected to such contacts of one cf the tens and units switches as will enable 11 to be signaled, while it will also be connected to such contacts of one of the thousands and hundreds switches as will enable 61 to be signalled.

If this subscriber makes a cail via the outgoing relay set the 100 tens and units switches t0- gether with the corresponding receiving switch RS will be simultaneously started up and caused to rotate in step. During the rotation of these switches the last two digits 11 of the calling number will be stored on the tens and digits storing relays of the toll relay set while the last two digits of the numbers of other subscribers who are also originating toll calls at the same time will be stored in the relevant outgoing relay sets. After these switches complete their cycle the 100 thousands and hundreds switches together with the corresponding receiving switch are started up and communicate the digits 61 to the thousands and hundreds storing relays of the relay set. Corresponding digits of other subscribers who are originating toll calls at the same time are also communicated to the relevant relay sets.

Considering now typical circuit arrangements whereby initiation of the calling line identification and initiation of the transference of the vstored calling number to the central exchange phone exchanges, finds still better application to large exchanges where its speed of operation is particularly advantageous.

In an .exchange having provision for more than 100 subscribers it is necessary to provide one set of SS switches on the basis of one switch per 100 lines (assuming a 25 point 8 wiper switch is used) in order to determine the tens and units digits of subscribers numbers, while in addition further switches must be provided for the purpose of determining the thousands and hundreds digits.

For instance, in a 10,000 line oiilce, 100 SS switches will be provided for determining the tens and units digits of the subscribers numbers and 100 further switches will be provided for determining the thousands and hundreds digits. Each P conduct-or will be connected to two contacts in the bank of the tens and units switch as already described while in addition it will also can be effected at suitable stages in a connection, it is found preferable to initiate identification when the outgoing relay set is seized and to initiate re-.transmission of the calling number when the calling party hangs up, and typical circuit arrangements for this mode of operation will now be described, reference being had to Fig. 5.

In this iigure, `the negative, positive and P leads shown at the top of the figure are connected on the left handside to contacts on the 0 level of a selector such as SR of Fig. 2 although in the more usual case where` a vdiscriminating selector repeater is provided in the calling satellite exchange, these leads will extend from the junction hunter switch associate-d with thefvdis-A criminating selector repeater. On the right-hand side the leads marked negative and positive .extend over the outgoing junction t-o the main exchange as shown in Figs. 2 and 7.

When the relay set ORS is seized, earth is extended over the incoming P lead to Voperate vrelay SI and this relay at its armature si2 completes an energising circuit to the slow-to-operate relay IS and at armature sill operates the slow-to-release relay SR.

During the operating time of -relay IS, earth is extended over armatures si3 and isl, and common lead I0 to either start up the identication equipment if it is not already in operation, or to bring about a subsequent repeat operation of 4this equipment if it is already in operation in response to the setting up of another call to be recorded.

The line identication equipment preferably comprises synchronously operated sending and receiving step-by-step switches as described with reference to Figs. 3 and 4. For the purpose of this description it will be assumed that the identification receiving equipment comprises a single switch RIS of the reverse drive type and it can readily be arranged that when this is started into operation the identification-sending equipment `is also started up and is subsequently operated in synchronism therewith through the identification cycle.

If the identification equipment is not already inV operation, the switch RIS will be in its home position I and the earth pulse extended over armatures S113 and is! will therefore cause magnet RISM to advance its wipers on to position 2 after which a pulsing circuit will be completed to the magnet over lead ll to which is connected a source of interrupted earth supply. The identification of the calling party will be thereupon transmitted over the P lead in the form of suitable A. C. pulses and will be received on relay PUR which is connected in circuit with a rectification arrangement comprising rectifiers MRC-MRF and which sets up the calling subscribers number on storage relays in the outgoing relay set as already described with reference to Figures 3 and 4.

If the identification equipment is already in operation when the outgoing relay set is seized a circuit will be completed to relay RI over the wiper RISZ in off-normal position which locks over bank and wiper RIS? until the identification equipment has completed an operating cycle when the wipers of switch RIS will return to the home position. Relay RI is now disconnected and during its slow release time, effected by the short-circuiting of its second winding over armature ril, an earth -will be extended to magnet RISM so that the identification equipment is caused to operate through another full cycle and thus ensure the storage of the last two digits of the calling number in the outgoing relay set, as while due to the position of the contacts representing such digits on the switch part or the whole of the identification may be stored during the cycle which was in existence this method of signaling permits of overlapping so that the second cycle may simply serve to ensure that no part of the identification has been omitted.

The calling number remains stored in the outgoing relay set until the end of the connection, and when the calling party releases, earth is removed from the private thereby releasing relay SI. Relay SI in releasing releases relay IS which has no effect at this stage, while during the slow release time of relay SR, the circuit of which is also disconnected, the magnet TSM of the transmitting switch TS receives an operating pulse and steps its wipers to position 2.

The switch TS controls the transmission of the complete number of the calling party, that is the digits representing the exchange 780 as well as the two digits 11 representing the particular calling line in that exchange. To understand the actual method or" transmission reference should be had to Figures 6 and 7.

A two letter code is employed for the various numerals 1-0 as follows:

This code is similar to that used for transmitting the calling line number to the relay set ORS but in this case it becomes important that the digits be transmitted in order starting from the first digit, whereas in the other case it was immaterial as the same storage would be effected whichever digit was transmitted first.

For each set of digits, i. e. tens, units, etc. to be received from the identifying equipment and to be stored in the relay set ORS, a set of rive storing relays V-Z is employed, the storing relays for the purpose of clarity being designated URV-URZ for the units digits, TRV-TRZ for the tens digits and so on.

Hence in the present example, since the digits 1l will have been received relays TRV and TRW, URV and URW will be operated.

Assuming that a maximum of five digits is to be transmitted from the relay set ORS to the central exchange, a 25 point uniselector will be utilised.

From Fig. 6 it will be seen that the bank of the transmitting switch which we will call TS is divided up into 5 groups of 5 contacts each, the groups being labelled TTH, Ti-I, H, T and U for the ten-thousands, thousands, hundreds, tens and units digits respectively. The ve contacts in each group are furthermore designated V-Z.

Earthed contacts of the units relays URV- URZ connect with the units group of contacts and contacts of the tens relays TRV-TRZ connect with the tens group so that in the present case with relays TRV, TRW, URV and URW Voperated the V and W contacts in both groups T and U will be earthed.

It will be remembered that it is desired to add the prefix digits 780 and this can be readily effected by earthing the Y and Z contacts in group H, and X and Y contacts in group TH and the W and Z contacts in group TTH.

Consequently when the switch TS steps its wipers to position 2 as previously described, the magnet TSM is connected over wiper TS and its associated bank to a lead i2 to which earth is intermittently applied, so that the magnet steps the wipers round at a speed determined by the rate of interruptions which is selected as being most convenient for sending the calling number in code to the central exchange. Each time magnet TSM is energised relay P operates in series therewith. Relay R operates every time the wiper TSI engages an earthed contact. When the wipers of switch TS2 are in position with the wiper TSI on contact V (Fig. 3) of the live contacts (TTI-I) allocated for the transmission of the ten thousand digit, a loop circuit over the speaking conductors will be completed to exchange E as follows: battery, resistance, normal springs of armature rl, armature pl, upper speaking lead, rectifier MRA, relay A, armature bl, lower speaking conductor, armature p2, resting contacts of armature r2, to earth. The rectifier MRA connected in series with relay A permits current to flow so that relay A operates and closes the circuit at armature a2 for magnet RSM of 25 point switch RS, which is similar to TS in that both are of thesame capacity and of the reverse drive type and has connection to 25 relays, each relay corresponding to one of the V, W, X, Y, Z relays allocated to a particular digit in exactly the same way as the contacts of switch TS are shown connected up. Consequently the switch TS and the switch RS step together. When wiper TS reaches contact marked W of the TTH group, relay R is operated and reversesl the direction of current flow over the loop including the speaking conductors, with the result that the rectifier MRA becomes nonconducting and the relay A therefore does not operate. On the other hand the rectifier MRB becomes conducting and the circuit previously completed through relay A is now completed through relay B. Relay B energises and at armature b2 completes the circuit for energising the magnet RSM of the switch RS and at armature b3 energises the relay connected to the second contact of switch RS which corresponds to Vthe contact W of the TTH group of switch TS.

It will thus be seen that whether relay A or relay B is operated the magnet RSM is operated while only when relay B is operated is a relay connected to bank of switch RS operated. Switches RS and TS therefore operate together.

As the switch TS steps round it will be appreciated that the relay R is similarly operated on the Z contact of the TTH group, the X and Y contacts of the H group, the V and W contacts which are connected to earth by the relays TRV and TRW respectively of the T group and the V and W contacts which are connected yto earth by relays URV and URW of the U group. Each time relay R is operated relay B will be operated and at contact b3 will cause the energisation of relays corresponding to the earthed contacts of switch TS. This method of signaling has'the advantage of fitting in very simply with the method of identication employed and it further has the advantage of reducing the junction holding time to a minimum, particularly in the case where the calling line number is transmitted over the connection after the conversation has terminated.

Referring again to Figure l it will be seen that exchange B has two common prefix digits 7, 8, while exchange C has one prefix 3 and so on. The wiring connections to the banks of the sending switches TS at the various exchanges necessary to enable these additional digits to be included will become apparent on consideration of the particular coding scheme employed.

In the case of toll calls originating at exchange E the same remarks may still apply with the exception that the digit storage and the addition of the common prefix 2 will take place in some intermediate relay set rather than an outgoing relay set.

In mixed digit areas employing for example 4 and 5 digit numbers it might be arranged in the former case either to leave all the contacts i in the group TTI-I (Fig. 6) unmarked, in which case none of the storage relays corresponding to this digit at exchange E will be operated, or to arrange to transmit some distinctive digit such as the digit 0, which is never used as an initial digit on the subscribers number, such a digit being arranged to produce a blank setting at the main exchange as far as the ten-thousands digit is concerned.

Referring to Fig. it will be noted that when the switch TS is off-normal, the relay G is operated over wiper TS3. This serves to connect earth to the private so as to keep the connection guarded and prevent the talking relay set ORS from being seized by another switch during the transmission to the main exchange. In case the line identication is to be started up on the reply of the calling party this could be effected in response to the transmission of a suitable signal from the' main" exchange, which signal might comprise battery reversal which would operate a relay bridged across the lines in the talking relay set ORS or alternatively some suitable form of A. C. signal could be transmitted which would be received `at the outgoing relay set on a suitably tuned A. C. relay.

These arrangements could also be employed in allV conditions where the identioation is to be initiated from themain exchange and can furthermore be used in connection with the retransmission ofthe stored number from the relay set in response to a signalv from the main exchange.

It will be appreciated that the invention is not limited to the .particular method of coding described and that anyother type may be utilised in place thereof. Moreover any other suitable kind of signal could vbe employed instead of alterhating current signals, while although the test conductor has been used for signaling throughout it is quite feasible that use could be made of other conductors which form part of the connection path. Furthermore, while reference 4has been made in the case of large exchanges to the use of two sets of .both sending and receiving switches, one set of each may only be needed if the banks are divided up into different sections which are used in turn. Again, one or more large capacity motor driven switches having a plurality of wipers some of which serve for sending and others for receiving, may be used in. place of a number of sending and/or receiving switches and thereby avoid the problems of synchronisation and operating noise. It is furthermore contemplated that the receiving switches may be replaced by groups of relays controlled from the sending switches in such manner as to simulate the step-by-step rotation of the receiving switches and prepare operating circuits for the various storing relays.

In the case of large exchanges, instead of lperforming identification over the whole exchange, it may prove more desirable to provide divided access facilities to intermediate relay sets from each ofthe various groups into which the exchange may be divided. As a result identication need then only be made over the particular group of lines from which the call has been originated,A the particular identification switches set into operation being determined by the access lead utilised. By these arrangements the amount of identification equipment required for a given exchange can .be reduced while at the same time a saving in battery drain is effected, particularly during light trafc periods.

From the embodiment described it will be seen that the invention provides a very novel, efficient, speedy and economical -method of identifying calling lines in systems of the type mentioned.

It should be understood further that the invention is not limited to storage on relay groups but that storage may be effected on stepping switches; for instance, the common apparatus at which the identification is to be registered may include a switch operated in synchronism with a switch at the line to be identified and a register switch may :be associated therewith at the beginning of a cycle and this register switch may -be stopped when the synchronously stepping switch at the calling line establishes a circuit over the connection. Successive switches may be taken into use for succeeding cycles, or alternatively one relay set may be provided for receiving a signal which in turn can control the position of a number of register switches successively to register the whole identification.

We claim:

1. In a telephone or like system, a plurality f lines, a register, switching apparatus common to said lines, means for extending a connection over said apparatus from any one of said lines to said register, means operated to connect with all of said lines in succession and as each line is connected with, to prepare said register for the registration of a different item of information, means in said register operated, over the connection extended to said register from said one line, responsive to said second means connecting with said one line, said last means effective to cause said register to register the item of information it is prepared to register as said second means connects with said one line.

2. In a telephone or like system, a plurality of lines, a plurality of points each having a register, means for extending a connection from any of said lines to any of said points, means operated to connect with all of said lines in succession, means individual to each point operated in synchronism with said last means to prepare the register at that point for the registration of a different item of information as said second means connects with each of the different lines, means individual to each of said points operated, over a connection extended to that point from one of said lines, responsive to said second means connecting with said one line, said last means effective upon such operation to cause the register at that point to register the item of information it is prepared to register as said second means connects with said one line.

3. In a telephone or like system, a plurality of lines, a plurality of points each having a register, means for extending a connection from any of said lines to any of said points, a progressively movable switch operated to make momentary connections to said lines, each of said points having a progressively movable switch operated in synchronism with said first switch to render that points register operable, at any ygiven instant, to register only the designation of the particular line to which said iirst switch is making connection at that instant, and means for operating a particular points register responsive only to said rst switch making momentary connection with a line from which a connection is extended to said particular point.

4. In a telephone or like system, a plurality of lines, a register, means operated to impress a signal upon all of said lines in succession and, as said signal is impressed upon each line, to prepare said register for the registration of a different item of information, a device common to said lines operable at different times and effective when operated to cause said register to register the item of information it is prepared to register at that time, and means operated independently of any control by said first means for associating said device individually with any one of said lines thereby to cause said device to operate responsive to said signal when same is impressed upon said one line.

5. In a telephone or like system, a plurality of lines, a register, means operated to impress a signal upon all of said lines in succession and, as said signal is impressed upon each line, to prepare said register for the registration of a different item of information, a plurality of responding devices each common to all of said lines, means for associating said devices individually with different ones of said lines, each of said devices thereafter responsive to said signal when same is impressed upon the line with which that device is associated and effective to cause said register to register the item of information it is prepared to register at the time said signal is impressed upon that line.

6. In a telephone or like system, a plurality of lines, a register, means operated to impress a signal upon said lines successively, means operated in synchronism with said rst means to prepare a plurality of different items of information successively for registration by said register, and a device associated individually with one of said lines throughout the time that said first means is operated to impress said signal upon the dinerent ones of said lines, said device operated by said signal when same is impressed upon said one line to cause said register to register the item of information prepared for registration at the time said device is operated.

'1. In a telephone or like system, a plurality of lines, a plurality of registers each common to all of said lines, means for associating each of said registers individually with a different one of said lines, means operated to place a predetermined condition on said lines successively, means individual to each of said registers operated in synchronism with said last means to prepare that register for the registration of a different item of information as said condition is placed upon the different ones of said lines, and means individual to each of said registers operated responsive to said predetermined condition being placed upon the line with which that register is associated to cause that register to register the item of information it is prepared to register at the time said condition is placed upon said line,

8. In a telephone or like system, a plurality of lines, a register, means operated to test said lines in succession for a predetermined condition thereon and, as each line is tested, to prepare said register for the registration of a diiferent item of information, and means operated whenever said first means tests a line having said predetermined condition thereon to cause said register to register the item of information it is prepared to register at that time.

9. In a telephone or like system, a plurality of lines, a plurality of registers, means operated to test said lines successively for a predetermined condition thereon, means individual to each of said registers operated in synchronism with said rst means to prepare a plurality of different f items of information successively for registration by that register, and means operated each time said first means tests a line having said predetermined condition thereon to cause a different one of said registers to register the item of information prepared for registration by that register at that time.

l0. In a telephone or like system, a group of lines, means for placing a predetermined condition upon any of said lines independently -of the other lines, whereby such a condition may exist on a plurality of said lines concurrently at times, means rendered effective responsive to said condition being placed upon any line and thereupon operated cyclically to test all the lines of said group, said means normally effective during a single cycle of its operation to identify all of said lines upon which said predetermined condition exists at the time of said cycle.

1l. In a telephone or like system, a plurality of lines, a point having a register, means for extending a connection from any one of said lines to said point, cyclically operative means for making momentary connections with said lines, said means effective to make a plurality of momentary connections with said one line during a single cycle of operation, means associated with said point operated in synchronism with said last means to prepare said register successively for the registration of different items of information, and means responsive to each momentary connection with said one line by said second means to cause said register to register the item of information it is prepared to register as said second means connects with said one line.

12. In a telephone or like system, a plurality of lines, a point having a register, switching apparatus common to said lines, means for extending a connection over said apparatus from any one of said lines to said point, cyclically operative means for making momentary connections with said lines, said means effective to make a plurality of momentary connections with said one line during a single cycle of operation, means associated with said point operated in synchronism with said last means to prepare said register successively for the registration of different items of information, and means operated, over y to cause said register to register the item of information it is prepared to register as said second means connects with said one line.

13. In a telephone or like system, a plurality of lines, a plurality of points each having a register, means for extending a connection from any of said lines to any of said points, cyclically operative means for making momentary connections with said lines, said means effective to make a plurality of momentary connections with each of said lines during a single cycle of operation, means individual to each point operated in synchronism with said last means to prepare the register at that point successively for the registration of different items of information, and means associated with each point operated responsive to each momentary connection of said second means with a line from which a connection has been extended to that point to cause the register at said point to register the item of information it is prepared to register as said second means connects with said line.

14. In a telephone or like system, a register, means for transmitting multi-digit numbers to said register, said means effective at times to transmit the first digit of such/numbers before transmitting the last, and said means effective at other times to transmit the last digit of such numbers before transmitting the rst, said register having one sub-register always operated by said first means to register the first digit of such numbers regardless of whether said first digit is transmitted before or after the last digit, and said register having another sub-register always operated by said first means to register the last digit of such numbers regardless of whether said last digit is transmitted before or after the i'lrst digit.

15. In a telephone or like system, a register, means for transmitting the digits of a multidigit number to said register in a certain sequence at times and for transmitting the corresponding digits of a multi-digit number to said register in a different sequence at other times, said register having means individual to each order of digit and always operated by said last means to register that order of digit in the multidigit number transmitted regardless of the sequence in which the digits of said number are transmitted.

16. In a telephone or like system, a register, means for transmitting multi-digit numbers to said register at different times, every one of said numbers having the same number of digits, said means effective at one time when transmitting one of said numbers to said register to transmit the individual digits of that number in a certain sequence, and said means effective at another time when transmitting one of said numbers to said register to transmit the individual digits of that number in a different sequence, said register having means individual to a particular order of digit in each multi-digit number transmitted to said register, said last means always operated by said first means to register said particular order of digit regardless of the sequence in which the individual digits of said number are transmitted.

REGINALD TAYLOR. GEORGE THOMAS BAKER. 

